The present invention relates to a display unit, and in particular to a display unit for displaying images viewable from two sides, whereby the image as perceived from one side can be different from the image perceived from the other side and the display unit is transparent or translucent when viewed from one of the sides.
The invention also relates to a method of displaying such an image as well as printers suitable for displaying a printed image and raster image processing (RIP) systems for preparing the data before display, particularly before printing.
Display devices with differing images on each side and being transparent or translucent from one of the sides are known from a variety of documents including EP-A-0170472 which describes a panel comprising a light permeable material and a silhouette pattern, comprising any arrangement of light restricting material which subdivides the panel into a plurality of discrete light restricting areas and/or a plurality of discrete transparent or translucent areas, characterized in that a design is superimposed on or forms part of said silhouette pattern so that said design is visible from one side of the panel only, and wherein said design is less perceptible from said one side of the panel as the level of illumination transmitted through the panel from said other side increases. A number of different vision effects are obtainable from different panels falling within the above definition. Thus clarity of vision can be maintained from the one side to the other side with the exception of the area covered by the design with clarity of vision through the whole of the panel from the other side to the one side. Visibility from the one side to the other side can be totally or partially obstructed while there is clarity of vision through the whole of the panel from the other side to the one side, in other words a unidirectional vision effect is obtained. Clarity of vision is obtainable from the one side to the other side except in the area of the design while visibility from the other side to the one side is totally or partially obstructed. Vision from either side can be totally or partially obstructed. In all cases through vision can be obtained in either direction through the panel when the level of illumination perceived through the panel from the far side of the panel sufficiently exceeds the illumination reflected from the near side of the panel. The transparent areas typically have dimensions ranging from 0.5 to 3 mm.
EP-A-0170472 and EP-00118638 describe methods of producing both the silhouette pattern and also the imposed design. The methods as described may be summarized as either sequential printing of the silhouette and/or the design using screen lithographic or similar ink printing processes with as exact a registration as can be obtained or a method in which a mask is applied and the printing processes are carried out through the mask onto the substrate. When the mask is removed, the silhouette pattern and image remain on the substrate only in the areas which the mask or stencil allow the ink to penetrate.
EP-A-0234121 describes further methods of printing such an image. The printing methods are limited to those including inks. Again a mask is described which is subsequently removed taking with it unwanted portions of the silhouette pattern and image.
U.S. Pat. No. 5,396,559 describes a security device for use on identification cards, monetary documents, and the like using a reference pattern and a message pattern each having the appearance of a random pattern of dots. The reference pattern is a dense pattern of randomly positioned dots, and the message pattern is a modulated version of the reference pattern in which the dots of the reference pattern are slightly repositioned by an amount depending on the gray value or color value of a message image at each dot location. The message image is decrypted and becomes visible with a range of gray values when it is viewed through a film transparency of the reference pattern. The dot pattern may be printed, embossed or recorded as a photograph or a hologram. Decryption of the message image may be accomplished by viewing through a contact mask, superposition of images of the message pattern and reference pattern, by viewing the message pattern through a mask positioned at a real image of the reference pattern, or like means.
Japanese patent application Kokai I (1993)-57863 describes a production of an image including transparent sections for areas of the image. A method is described in which a decorative sheet is prepared by registration printing in the order of a rear pattern layer, a covering ink layer and a front pattern layer on a transparent plastic sheet in such manner that a plurality of small transparent portions remain in the image. No description is made as to how the registration printing should be carried out.
Japanese patent application Kokai I (1989)-69397 describes a method of producing a transparent plastic or glass substrate with a printed layer including a plurality of holes. The method includes printing the image onto a second substrate, perforating the image and second substrate and then transferring the image only from the second substrate to the transparent plastic or glass substrate.
The present invention provides a method of displaying an image on a display device having first and second sides, said image including a light restricting silhouette pattern having a plurality of first transparent or translucent areas, and at least one design layer having at least one colour, said at least one design layer being visible from one side of said display device and substantially less visible from the other side, said image being substantially transparent or translucent: as viewed from the other side, comprising the steps:
1) providing at least a definition of said design layer to a computer,
2) generating a computerized version of said design layer with the computer,
3) outputting the computerized version of said design layer to said display device, the computerized version of said design layer being modified to subdivide said design layer into a plurality of second discrete transparent or translucent areas and other areas, and
4) displaying said modified design layer and said silhouette pattern with said first and second transparent areas being in registry.
The present invention also includes an article having a conformable substrate, comprising: a colorant receptor layer and a light restricting layer on said substrate, said light restricting layer having a plurality of first transparent or translucent areas.
The present invention also includes an article comprising: a polymeric substrate having a composition comprising vinyl chloride resin, optional acrylic resin, optional plasticizer, and optional stabilizer, wherein the composition is formed on a polymeric release liner having smoothness of a Sheffield value of from about 1 to about 10, and a light restricting layer and a design layer on said substrate, said design layer including at least one color layer, said light restricting layer being subdivided into a plurality of first transparent or translucent areas, said design layer being subdivided into a plurality of second transparent or translucent areas, and said first and second transparent areas being in registry.
The present invention further includes a printer for receiving a print file including color separated image data, light restricting layer data and transparency data, and for printing the color separated image and the light restricting layer data including transparent areas in both the color-separated layer and the light restricting layer in accordance with the transparency data.
The invention further includes a raster image processing method for raster image processing of a print file including color separated image data, light restricting layer data and transparency data, comprising: operating on said print file to generate raster image bitmaps for said color separated image data and said light restricting layer data, and introducing said transparency data into said raster image bitmaps for said color separated image data and said light restricting layer data so that the transparent areas in said color separated image raster bitmap and said light restricting layer bitmap are in registry.
The invention includes in addition a raster image processing system for raster image processing of a print file including color separated image data, light restricting layer data and transparency data, comprising: means operating on said print file to generate raster image bitmaps for said color separated image data and said light restricting layer data, and means introducing said transparency data into said raster image bitmaps for said color separated image data and said light restricting layer data so that the transparent areas in said color separated image raster bitmap and said light restricting layer bitmap are in registry.
The invention also includes a graphics computer based system for creating graphics images including color separated layers and light restricting layers, comprising: first input means for image data, means for generating color separated image data from said image data, means for generating light restricting layer data, second input means for transparency data, and means for outputting a display file including said color separated image data, said light restricting layer data and said transparency data.
The present invention may provide conformable articles including transparent areas in images, methods of providing the same and printers, computer graphics systems and raster image processing systems and methods for producing images on the articles at low cost.
The present invention may provide conformable articles including transparent areas in images, methods of providing the same and printers, computer graphics systems and raster image processing systems and methods for producing images on the articles which allow variability in image not previously achieved.
The invention with its embodiments and advantages will be described with reference to the following drawings.